8.9.3.27 IfcCurveBoundedSurface
8.9.3.27.1 Semantic definition
The IfcCurveBoundedSurface is a parametric surface with boundaries defined by p-curves, that is, a curve which lies on the basis of a surface and is defined in the parameter space of that surface. The p-curve is a special type of a composite curve segment and shall only be used to bound a surface.
The outer boundary shall be either defined by:
- an IfcOuterBoundaryCurve a closed composite curve on surface for the definition of an outer boundary, in this case the attribute ImplicitOuter has to be set to FALSE, or
- an implicit boundary of the bounded surface, e.g. the u1, u2, v1, v2 of IfcRectangularTrimmedSurface, in this case the attribute ImplicitOuter has to be set to TRUE.
Informal Propositions
- Each curve in the set of Boundaries shall be closed.
- No two curves in the set of Boundaries shall intersect.
- At most one of the boundary curves may enclose any other boundary curve. If an IfcOuterBoundaryCurve is designated, only that curve may enclose any other boundary curve.
8.9.3.27.2 Entity inheritance
-
- IfcSurface
- IfcAnnotationFillArea
- IfcBooleanResult
- IfcBoundingBox
- IfcCartesianPointList
- IfcCartesianTransformationOperator
- IfcCsgPrimitive3D
- IfcCurve
- IfcDirection
- IfcFaceBasedSurfaceModel
- IfcFillAreaStyleHatching
- IfcFillAreaStyleTiles
- IfcGeometricSet
- IfcHalfSpaceSolid
- IfcLightSource
- IfcPlacement
- IfcPlanarExtent
- IfcPoint
- IfcSectionedSpine
- IfcSegment
- IfcShellBasedSurfaceModel
- IfcSolidModel
- IfcTessellatedItem
- IfcTextLiteral
- IfcVector
8.9.3.27.3 Attributes
| # | Attribute | Type | Description |
|---|---|---|---|
| IfcRepresentationItem (2) | |||
| LayerAssignment | SET [0:1] OF IfcPresentationLayerAssignment FOR AssignedItems |
Assignment of the representation item to a single or multiple layer(s). The LayerAssignments can override a LayerAssignments of the IfcRepresentation it is used within the list of Items. |
|
| StyledByItem | SET [0:1] OF IfcStyledItem FOR Item |
Reference to the IfcStyledItem that provides presentation information to the representation, e.g. a curve style, including colour and thickness to a geometric curve. |
|
| IfcSurface (1) | |||
| * | Dim | IfcDimensionCount |
This attribute is formally derived. The space dimensionality of IfcSurface. It is always a three-dimensional geometric representation item. |
| Click to show 3 hidden inherited attributes Click to hide 3 inherited attributes | |||
| IfcCurveBoundedSurface (3) | |||
| 1 | BasisSurface | IfcSurface |
The surface to be bounded. |
| 2 | Boundaries | SET [1:?] OF IfcBoundaryCurve |
The outer boundary of the surface. |
| 3 | ImplicitOuter | IfcBoolean |
No description available. |
8.9.3.27.4 Formal representation
ENTITY IfcCurveBoundedSurface
SUBTYPE OF (IfcBoundedSurface);
BasisSurface : IfcSurface;
Boundaries : SET [1:?] OF IfcBoundaryCurve;
ImplicitOuter : IfcBoolean;
END_ENTITY;